Yahoo CEO Marissa Mayer announced today at TechCrunch Disrupt that Yahoo monthly active users are up 20% to 800 million globally, including 350 million monthly active users on mobile. Mayer said those figures do not include Tumblr.

Yahoo in April of last year began secretly scanning the incoming emails of its hundreds of millions of users to comply with an order from the U.S. intelligence community, a move that prompted at least two company officials to leave,...